Means of commingling fluids



June 18, 1940.`

W. R. ECKART MEANS OF COMMINGLING FLUIDS Filed My 1e, 1938 3 Sheets-Sheet 1 JNVENTOR, wim/,4M /Q Ecm/2 BYQ T TORAEY June 18, 1940. w. R. ECKART uEANs oF couumGLmG FLUIDs 3 Sheets-Sheet 2 Filed Ilay 16, 1938 L/AMH. [CMA/2r /ITTORNEY W. R. ECKART MEANS OF COMMINGLING FLUIDS Filed lay 16, 1938 3 Sheets-Sheet 3 Patented June ..18, 1940 UNITED s'rii'nzs:

` Manus oF COMMINGLING FLUlDs william n. Eckart, sanmarinn, cans., animar to C. F. Braun & Co., Alhambra, Calif., a corporation of California Application May 16,1938, serial No. 208,202 'z claims. v(ci. zel-114i 'I'his invention relates to liquid-gas contact apparatuses, and particularly 'pertains to a Means of commingling fluids.

In many chemical, petroleum engineering, and l similar processes, the transfer of one or more components from one material to another isinvolved.

Absorption, stripping, fractionation, extraction, 'y drying, etc., may be mentioned as operations requiring such transfer. 'Ihe transfer from one 10 material to another may or may not include chemical reactions. In such cases, time of contact may be a necessary. consideration in the operation of the process'. Intimate contact or mixing of the fluids is essential, as these processes 1| depend upon establishing or closely approaching equilibrium relations. In continuously operated processes, multiple contacting of the fiuidsilowing Yin a counter-current manner is in ,general necessarily required. e The above-,mentioned .of Fig. .4.

through a bubble-column disclosingv the application of the present invention. o

Fig. 21s a view in transverse horizontal section through the bubble column as seenon the line 2-2 of Figure l. and disclosing the bubble-cap 5 arrangement.

Fig. 3 is an enlarged view in side elevation showl ing one .form'of the bubble-cap.

Fig. 4 is an enlarged view in plan showing the bubblecap disclosed in Fig. 3. 10

Fig. 5 is a view in transverse vertical section through the bubble-cap as seen on the line 5,-5

Fig. 6 is an enlarged .view in vertical section through^fanother form ofthe bubble-cap provided ll with a center bolt. o

Fig. 7 is a fragmentary view showing a bubblecapl of the present design with a plurality of eductor rings.

I processes lor operations may be conducted Referring more particularlytothe drawings, Il 20 columns of various `types containing either packing, perforated trays, or bubb cap trays. l

The present invention relat s particularly to the design and use of a novel type of bubble-cap in a column to obtainthe required intimacy of contact and to extend the limits or range of such' contact and agitation beyond the limits usually established with bubble-caps of ordinary design. The present invention, therefore, perrnitsthe use N of a lesser number of caps in a given cross-section f area of column; allows increased spacing loetween the caps, thus permitting increased columnl Aofliquid flow without building up. an excessive hydraulic gradient between the down pipe and Il' .weirs, and at the same time, prevents channelling of the downwardly flowing nuid between the bubble-caps and through the trays without contacting the upward flowing fluid.

The present invention contemplates the prof- Il vision of a bubble-column having an outer shell,

a plurality of trays therein upon whichliquid may accumulate and from which liquid may pass successively from one tray fto another after a desired accumulation has taken place. The trays carry a plurality of caps of novel design and construction which include means for insuring that -the gas will be introduced into the liquid flowing across a vtray substantially at the bottom ofthe body of the accumulated liquid on the trayand in a manner to create a maximum amount of agitation in the liquid whereby a high degree of liquid-gascontactwill be produced.

The invention is illustrated by way of exampleY in theaccompanying` drawings in which:

Figure 1 is a View in central vertical"section. u

dicates the shell `of a bubble-column tted with'\ bottom closure Il and `a top closure l2, which Aclosures are secured in position in any suitable manner, A gas outlet, pipe t6 communicates with the interiorof the column through the top closure 26 I2 'and permits the upward flowing gas to pass out vfrom the column. Disposed at spaced intervals vacross the shell, and at different heights therein', are trays |1, upon which oil from an oil inlet conduit I3 may be delivered. These trays Aare pro- 30 vided with overflow or down pipes IB, one of which is here -shown' for each tray.

By reference to Figure -2 of the drawings, it will'be seen that the down pipethere shown repre'- sexits the segment of a circlel It is to be under- 35 stood, however, .that this sectional formation is not necessarily the only type which may be used,

butthat in different installations, the down pipes may be arranged and shaped so that .they will conform suitably to the design and tray arrange# 40 ment. It is also to be noted in vFigure 2 that the down pipe from super-adjacentltrays are shown as lbeing disposed upon `diametrically opposite sides of the longitudinal center axis of tle shell. In' certain installations, this arrangement may 4l be-varie'd to meet the` conditions present and` to insure Vthe necessaryuniform distribution andA flow 'of the fluid over the trays and with relation to each other, Thus, the down pipe arrangement is optional toinsure-that the li'iuidwill flow across 60 each ltray from its point 'of induction to its point of eduction without channelling and with a maximum intimate comminglingaction with the gas. The level of the. mouth of the upper ends of the down pipes I8, as-indicated at acts as weirs ff and are definitely set to establish the level at which accumulated liquid on a -tray will overflow. In some instances, the weir portions may be vertically notched as indicated at 2|. I'he level of the discharge ends 22 of the down pipes I3 are on a plane lower than that of the upper ends 20 of the down pipes associated with the same tray, thus insuring that the down pipes I8 will be liquid sealed at `their lower ends, and that the gas passing through the column must pass upwardly through the trays and through bubble-cap units 23.

One form of bubble-cap unit is indicated in Figs. 3 to 5, inclusive,'of the drawings. It is to be understood that while the structure lthere shown represents the preferred form of bubblecap embodying the present invention, that the cap may be designed differently to accommodate constant or variable velocity flow of fluid.

This cap comprises a tubular riser 24, a bell and an eduction ring 26.i The tubular riser extends vertically and has a mouth 21 at its lower end through which gas is introduced. 'I'he upper end ofthe riser is formed with a mouth 28, pref erably but not necessarily, of reduced diameter asncompared with the lower mouth 21.\ The lower 'I'he throat 34' mouth 2l is-formed with extends into an opening 30 formed through a tray l1. A shoulder 3| is formed around the lip 29 and rests upon the upper face of the tray l1. Attention is directed to the fact that the wall of the riser is progressively reduced in thickness from its lower end to the mouthV 28, and that the opening 32 which occurs through the riser for the accommodation of the owing gas progressively decreases in dianieter from its influent end to its eiiiuent end. This insures that as the gas ilows upwardly through the central passageway 32 of the riser 24 its velocity will be progressively and uniformily accelerated. This acceleration will be continued as the gas passes from the disthe riser, since vthe bell 25 which extends over th'e thereof, is so designed as to combine with the wall of the riser 24 to'form a gas passageway 33 which is progressively restricted in widthl and area and continues the uniform acceleration of thegas as itows there along.

The bell 25 is formed with an upper end wall representing an invertedcone, the apex of which is in alignment with the longitudinal center' of the riser and which apex 'projects downwardly with relation to the mouth 28 ofthe riser to provide a communicating passageway 34 along which the passageway 32 of theriser to the passageway 33 which is in an -enlItwilLbe understood that the passageway v33 enthe gas may ow from veloping position over and around the riser.

circles the riser completely, and that it terminates with an annular discharge throat 34 which directs the gas horizontally along the upperface I 'l nd in a plane. substantially to'the center axis of the riser. is also progressively contracted in the direction of flow of the gas. The lower edge of the bell 25 is formed with an out-turned lip 35 which substantially follows the contourof lie riser 24 and provides clamping means for the While the bubble-cap structure` is here shown it is to be understood that.

as being circular, the cap may be of-any other symmetrical form in order to meet with the problem tn be Solved in anyA particular tray arrangement. devices diiering from those here shown for holdate face 38 is formed by 'charge uids into a lip portion 29 which riser and circumscribes the sides" Various Y ing the assembled parts together may be used to' meet the necessity of construction and manufacturing requirements. y

Disposed in an encircling position with relation to the bell 25 and its lip 35 is an eduction ring 26. This ring is formed with an outwardly and downwardly flaring wall section 31 which'at its upper end stands substantially vertical, and at its lower end is substantially horizontal. An arcuouter face of the bell 25 audits lip 35. This creates a passageway 39 between the ring and the bell which passageway progressively decreases in sectional area in the direction of flow of fluid downwardly and outwardly through it.

'I'he body of the ring is held in spaced relation to the upper faceV of the tray by a plurality of lugs 40 and 4I which are. cast on the underside of the ring and hold the discharge lip 42 of the ring in spaced relation to the upper surface ofthe tray to create an eduction passageway 43 into which fluids fiowvflrom the passageway 38 and th'e passageway 34', and from which a cincumscribng series of radially moving jets will disthe body of fluid which has accumulated to a suitable level on the trays.

The rings are provided posite 'sides with bosses l4'4 which on their inner sides have o'verhanging lugs 45. 'I'hese lugs engage the upper surface of the'ilange portion 35 of the bells 25 and hold these bells down. The bells are formed at their upper ends with a series of lugs 45' which have an angular seat 45, the horizontal portion of ,which rests against the upper end face of the riser 24. ,The lugs 45' rest on the riser 24 and hold the bell25 with its lip 35 in spaced relation to the riser and the tray. A substantially vertical portion of these lugs extend downwardly over the outside of the riser to center the bell with relation to the riser. Cap screws orl bolts 35 extend through the bosses-44 and hold the entire bubble-cap structure in an assembled positionover opening 30 in a tray.

Attention is directed to the fact that in this Particular construction it is not the ring adjacent to the possible for a riser to fall through a tray in the event that it becomes unfa'stened, and that furthermore the use of the circumscribing eduction cap screws make it possible to eliminate a center fastening bolt, which in many instances extends downwardlygthrough the bell 25 and engages a web in lthe opening 30 over the tray l1 as, shown in Fig. 6. This insuresthat the volume of gaa mayy flow through a bubble-cap without being disturbedlor obstructed in its flow until it is projected into the body of liquid within which the bubble-cap structure is partially-submerged.

Attention is also directed to the factthat the eduction ring not only holds 'the bubble-cap assembly in position upon the tray, but that it proring and the at diametricauy opvides an eductionnozzle through which fluidi'rom y.

bring the'se fluids into' incoming gas and to iiuidon the tray in the may be drawn into passageway 39 and todlsa velocity greater than that customary in bubblecaps ol! present design..v It 'will be recognized further that the high velocity ofthe gas .or Vvapor will create a' jetting action which not only will disturb the accumulated liquid `throughout its Vtirely new spacing arrangement of the down pipes and bubble-caps of any particular tray. As will be hereinafter pointed out', the bubble-caps here describedV may' be widely separated from each other to accommodate large volumes of liquid Y which flow across thetrays and between the caps without building up'an'excessive hydraulic gradient. hydraulic gradient fromv building'up on a tray due to increased velocitybetween bubble-,caps which would cause the depth of liquid at successive .rows ot caps to be varied. with the result vhaving the least submergence and gas wouldnot ilow through the caps having greater submer- .gence, due to the increased pressure head of the greater depth of lliquid. a

By use of thebubble-cap structure here shown, and by the spacing which is provided, ay substantially uniform hydraulic gradient is Imaintained on each tray and thus an eiiicient degreel n of contact is established `between the. `commingling iluids, wh'ile insuring that maximum' volume of saidvllulds desired may pass through the column. lit is to be pointed out 'that here.

tofore in bubble-cap arrangement, the gas was merely discharged into the body voil liquid accumulated 'upon a tray .and liberated from substantally vertical slots in the\lip(of the bubblecap at a level materially above that of thel This is essential in order to prevent the 1 tendency for the liquidto channel, the gas.

is projected at allrates' ,ofi-ilowentirelyalong the oor ofthe tray.A -Itwi ll,y furtherbe apparent vthatthere will be moretime of contact between the`fluids,fand a more violent and uniform agitation of the huids. vIt will also be recognized' that since the center of the gas pressure below the liquid surface is always substantially constant in each bubble-cap for agivenl height of liquid onv its tray, and that .the passageways through which` the gaswill ow are stream-lined to reduce/friction and eddy losses to a minimum,

.the total pressure drop through the bubble-cap assembly and the liquid will vary primar-ily only u with the velocity of the gas flow. Thisis contrary to the condition in the ordinary cap wherethe center of pressure below the liquid surface increases as the'velocity of gas increases, so that the head of liquid through which the gas must risegalso increases. Furthermore, the increased velocity with which the gas is discharged andq the fact'that it always .issues from the:bubble cap,.close to theA floor of. the tray, will vprevent` that the,gas would then llow vthrough the caps a Lany possible accumulation of deposits Vsuchv ,as

. gum, sludge, solids; andother foreign material,

door surface of l-the tray., In addition the ordinary caps are generajlly'set at a distance above the tray of from l/g" to V2. to allow for any accumulation of deposits otsludge on the tray without interference with the openings ofthe cap slots.` Thus with this 'arrangement the eilective gas passageways will` occur in the center'l of the body of accumulated liquid and at a level materially above the surface of .the tray. ThisV will produce channelling of the liquid. With such bubble-caps yoffordinary 'design and with Va'given Adepthiof liquid on the tray. lsubstantially determinedfby thev weir height and perimeter the depth of gas discharge `below the liquid surface, the time ot contactbetween liquid and gas,V the depth of liquid contacted by` the gas, and the degree of agitation, thepressure drop throughthe liquid will vary with the volume of gas how. Therefore the efllc'iency of all oiffithe trays, are Acovered' with liquid to a.v

the tray' is byall of these" Variables.

Such caps are generally designed to have the gas discharge' throughoutY-the. whole depthof the cap-slots at IullI-or maximum load. 'Even `velocity and-directed along the floor4 of the trays under'a conditionof maximum hydraulic zhead.-

The entireV area of liquid :occurring between neighboring bubble-caps`A will be agitated throughout to insurea maximum lcommingling of .the gas andfliqidand therewill `not be a around the discharge opening and u`pon the' trays, thus insuring against clogging of the apparatus.

.Referring particularly tol the form' of, the in- .vention shown in Fig. 6, it will be seen that a riser 41 is provided havin'g4 a shoulder ll which engages the under face of a tray I'i. The'inside of the bell of the cap 50 'has nswhieh center the bell relative to the riser. 'I'he bell 50 which extends downover theriser and is formed at its outer edge with a lip 5| here shown as resting on ashoulder szbof a rib sa `on an with relation to the tray I'l'. f Inthe form of the device shown in Figure V7 a plurality o f eduction rings 5l are provided nested onegwithin the other and disposed -aroundthe marginaledgeyil of the..

bell...

In operatlonof the presentl invention Israels I -delivered iii-tothe bottom o i'. the shell 'Il through a gas-'delivery pipe l58,.;51he gasv inlet isf-always abo'vefthe liquid level maintained infthe bottom` ofthebubble'column, and above thefll'quid outlet. oil' draw-oi! pipe -rIihalso connects with the bottom portion ofvthe'shell at alevel below:

.the gasinlet pipe 5I. Liquid,y is then fedinto, theupper' end of the shell '.-through thel conduit I3 anidawilll accumulate upon the trays -until fdesired level.

, fe tothe violentagitationproduced'bythe.

gas introduced intov the liquid'at higher velocity `manV at present customary, itis evident that mtimate Acontact of the gas and-` liquid-will be created l'over a much larger area` than is now `usuallydthe case, thus making it possible to place vthe'bubble-caps at greater' distance fromv each "other, is now common without decreasing the ciilciency of the apparatus and ,without posat the eductor slots slbilityV that theliquid will channel betweenthe caps -without intimately contacting the gas.- -It wm also be` evident that. a, violentfagitaucn vof-` the liquidwill be created-and that (ther action of theeductor rings. will the-liquid lyingixnmediately around the captovbe drawn in by aspiration and to, bel discharged with the gas y 43, Such liquid contacting 15 tation as it flows into the riser.

the gas passing through the eductor ring will bemaintained in intimate contact over a longer period of time than is now usual, thus insuring a more eiiicient action. The gas passes upwardly through the center passageway 32 of' the riserv as indicated by the arrow A in Fig; and it will b'e discharged into the mouth 23 and will be deflected into the inverted cone shaped top of the bell 25, thereafter passing around the lip of the riser as indicated by the arrow b in Fig. 5, and then; downwardly along the passageway 33 to be discharged from the bell at 34' into the passageway 43 of the `eduction ring and to pass along the surface of the tray Il as indicated by the arrow c. At the same time uid from the body of liquid will be drawn in through the passageway 39 asindicated by the arrow d in Fig. 5 and will commingle with the gas which is passing outwardly through throat 34'.Y All of the surfaces along which the gas passes have been stream-linedto reduce loss of pressure head as might occur due to sudden change. of

tray as indicated by the line This permits minimum contraction of the stream and rrevents losses due to eddying of the gas from cavi- Gas will thus flow in'a smooth even stream accelerating progressively from the induction-end of the opening 21 of the riser to its point of discharge through the throat 43. As Athe gas rises through the caps and ,contacts the liquid on the successive trays multiple action occurs, the number of trays and contacts being determined for the particular operation' being, performed and the degree of equilibrium to be established.

The eductor rings 26 are provided with lugs `4l and 4| to break or divide the gas stream-in a horizontal plane into separate lines of gas'in a manner similar to that accomplished by vertical slotsv in ordinarybubble-cap construction. This insuresy breaking up of bubbles and a high degree of intimate contact ot the gas" downwardly through the throat 39 and cause this liquid to commingle with the gas, at the bottom of the accumulated mass of liquid on the tray and along the surface of the tray. It will also be evident that as the gas and the liquid dscharge from the eductor ring) a disturbance of the liquid will be created above and outside of. the eductor ring and inthe general direction of gas flow. This insures that the entire accumulated body of liquid upon the tray will be disturbed and agitated, thereby producing-a max'- mum intimate' contact between thegas and the liquid particles. In the use of the structure shown in Fig. 7 where a plurality 'of eductor 1 rings 54 are provided, it will be evident that the range of agitation and recirculation of the fluids will 'be extended. It will further be recognized that eductor rings of the type here disclosed might be used in conjunction. withv other types of bubble-caps in which the gas is. ejectedf therefrom beneath a submerged lip, thus obtaining;

v to meet a particular problem i'nli'quidl-gasV contact, and that the Vcaps may .be designed to de termine and control the velocity of iluids through the apparatus. For example when the caps are designedv for increasing velocity through the passages the cross-sectional. area. of the caps:

are arranged so that even withv thel same spacing as with ordinary caps they will insure thaty a. greater volume of liquid may pass; between thecap with the same hydraulic gradient` as. compared with ordinary caps of thesame diameter..

.It will thus be seen that the bubble-cap struc--v ture here disclosed provides means. readilyI adaptable in design to meet anyproblem which. might arise in liquid-gas contact apparatus, both as to the character of the products to be commingled. and as to the velocities and pressures.

under which they flow, and -that by the arrange- [ment here shown an increased commingling action will result as compared with the ordinary bubble-caps While I have shown the preferred iorm. of'my' .invention and the preferred method of practicing. the same, it is to be understod thaty variouschanges might be made in`the combination, con-- .struction and arrangement of partsand various changes in the'steps of the method without departing from the spirit of my inventioh` as shown and disclosed. It will be understood' that while certain elements have been described as being tubular and are shown as being circular incross-section that they may 7be of any cross-v sectional shape desired without departing frcm the spirit of the. invention.

Having thus described. my invention, whatv Il claim and desire to secure by Letters Patent is: i; A bubble column comprising a shell, a tray therein upon which liquid may accumulate to a opening therethrough,.a`bubb1e: cap mounted over said opening formed with. a central. tubular riser through which a gas may flow" upwardly and circumscribed by a cap spaced lfrom the.

tubular riser and.throughwhi`cln said gas may' -desred level, said tray being formed with anI flow downwardly and. be projected outwardly i'n a path of travel substantially parallel toy the:

piane of they upper surface of the tray and be neath. the body of 'liquid accumulated thereon they passageway withinI the bubble cap= andl through which the gas iiows being progressivelyk constricted in sectional area.-'and an ed'uction.

ring circumscribing the bubble cap" in the area of gas: discharged therefrom, saidI ringip'roviding a throat through which the accumulateda'liquidsl upon. .the tray may be drawn by' the,- discharging way" through the riser progressively decreasing. lin

diameter from its inuent to its` eiiiuentk end -andA av bell element fittingr over; the eiiluent end. of' the riser and extending-downwardly to a ,..iintgadhjacent theJ face o f the'traypupon: which thefri'ser u is disposed, the bell being spaced with relation to fluids fr 5 downward y and then outwardly along the upper face of the tray, the said downwardly and outwardly directing fluid passageway being progressively'reduced in sectional area in the direction of the flow of fluid, an eduction ring circuml Scribing Athe lower circumference of the bell and having a wall spaced therefrom and conforming ,substantially thereto and' extending outwardly which tray an accumulated body of liquid occurs,

which structure comprises Va riser mounted over said opening, said riser being tubular and hav- 25 ing unobstructed openings at its opposite ends, the passageway through the riser progressively decreasing in diameter from its influenttoits eflluent end and a bell elementtting over the effluent-end of the riser and extending down- 30 wardly to a point adjacent the face of -the tray upon which the riser is disposed, the bell being spaced with relation to the outside of the riser and the surface of the tray whereby a uid space will occur to receive uids from the riser and 35 to direct sa'id fluids downwardly and then outwardly along the upper face of the tray, the said downwardly and outwardly directing uid passageway being progressively reduced in sectional area in the direction of the iiow of fluid, and educ- 40 tion ring circumscribingthe lower circumference ofthe bell and having a wall spaced therefrom and conforming substantially thereto and extending outwardly therebeyo d whereby a throat will be formed betweenthelow rportion-of the bell and 45 the eduction ring to direc liquid into the stream of uid passing from the space between the eduction ring and the riser, said throat being reduced in sectional area progressively in the direction of the flow of fluid.

50 4. A bubble cap structure adapted to be mount-` ed over an opening in a bubble column tray and upon which tray'an accumulated bo`dy of liquid occurs, which structure comprisesa riser mounted over said opening, said riser being tubular and 55 having openings at its opposite ends,-the passageway through the riser progressively decreasingin diameter from its influent to its elliuent en'd and a bell element fitting over the etlluent end of the riser and extending downwardly to apoint ad- 50 jacent the face'lof the trayupon which the riser fis disposed, the bell being spaced with relation the outside of the riser'and the surface of the tray whereby a fluid space willioccur to receive 65 downwardly and then outwardly along the upper face of the tray, the said downwardly and.out Y wardly directing uid passageway being progressively reduced in sectional area in the direction ofthe flow of fluid, an eduction ring circumscribing the lower circumference of the bell and having a wall spaced therefrom and conforming substantially thereto and extending outwardly therebeyond whereby a throat will be formed be` 75 tween the lower portion o f the bell and the educfluids fromthe riser and to direct said fluids'.

tion ring to, direct liquid into the stream of uid passing from the space betweeny the bellr andthe l 5. A bubble-cap structure adapted to be mounted over. an opening in a bubble column tray and upon which tray an accumulated body of liquid occurs, which structure comprises a risermounted over said opening, said riser being tubular Avand having 'openings at ii'fS opposite ends, the

passageway through the riser. progressively del creasing in diameterI from its influent to its effluent end and a bell element fitting over-the eiiiuent-end o f the riser and extending downwardlyto a point adjacent the face of the tray upon which the riser is disposed, the bell being l5 spaced with relation to the outside ofthe riser andthe surface ofthe tray whereby a fluid space will occur to receive fluids from the riser and to direct said uidsudownwardly and then outwardly along the upper face of the tray, the said downwardly and parallel directing fluid passageway being progressively reduced in sectional area -in -the directing of vthe flow of fluid, an educting -ring circumscribing the 'lower'circumference of the bell and having a wall spaced therefrom and conforming substantially thereto and extending 6. A bubble-cap structure adapted to be mount- I ed over an opening in a bubblecolumn tray and Y upon which tray an accumulated bodyj-of liquid occurs, which structure comprises a riser mounted over said opening, said riser being tubular and having openings at its opposite ends, the passagewaythrough the riser progressively decreasing in diameter fromits influent to its effluent end and a bell element fitting overthe eiiluent end of the riser and extending downwardly to a point adjacent the face of the tray upon which the 45 riser is disposed, the bell being spaced with relation to the outside of the riser andthe surface of the' tray wherebya fluid space will occur to 4receive fluids from the riser and to direct said fluids downwardlygand then outwardly along the upper face of the tray, the said downwardly 'and outwardly directing iuidv passageway being progressively reduced in sectional areavin the direction of the ow of fluid, an eduction ring circumscribing the lower circumference of the bell and having a wall spaced therefrom and conforming substantially thereto and extending outwardly therebeyond whereby ,a throat will be formed between the lower portion of the bell and the eduction ring to direct fluid interne stream `f of liquid passing from the space between the bell and the riser, said throat being reduced in secwardly directed passageway through which fluid may be directed-into the jet of the fluid owing rfrom beneath the rst 4inentionededuction ring.

'7. A bubble column comprising a shell, a tray therein, a riser extending upwardly from the tray andhaving an unobstructed passageway therethrough. a bubble cap :positioned over the riser and in spaced relation thereto, the4 lower marginal lip of the cap being adjacent to the face of theringr mounted uponthe vface of the tray and circumscribing said passageway, sa'id ring being spaced from the outer surface of the cap andA forming a downwardly and outwardly direct passageway between and around the bubble-cap.

I .WILLIAM R. ECKART. 

